# hsa-miR-520d-3p and hsa-miR-449a are Candidate MicroRNA Regulators in Multiple Sclerosis

## TL;DR

This study identifies hsa-miR-520d-3p and hsa-miR-449a as microRNAs with reduced expression in multiple sclerosis patients, suggesting their potential as biomarkers.

## Contribution

The study identifies two novel microRNAs, hsa-miR-520d-3p and hsa-miR-449a, as potential biomarkers for multiple sclerosis diagnosis.

## Key findings

- hsa-miR-520d-3p and hsa-miR-449a are downregulated in MS patients compared to healthy controls.
- These microRNAs target the Notch1 signaling pathway and downregulate genes like LASP1, TUBA1C, and S100A6.
- RT-PCR validation showed significant differences in miRNA expression levels between MS patients and controls.

## Abstract

An incapacitating chronic inflammatory neurodegenerative illness, known as multiple sclerosis (MS), is characterized by lymphocyte infiltration into the central nervous system. We aimed to identify specific miRNAs whose altered expression correlates with MS diagnosis and therapy selection, which could be biomarkers for these aspects of the disease.

The GSE21079 dataset was obtained for this study using Geoquery version 2.50.5 from the Gene Expression Omnibus database. The miRNAs exhibiting the highest variance were selected,
and a miRNA-miRNA interaction network was constructed through a Bayesian network utilizing the bnlearn R package (version 4.7.1).
The adjacency matrix generated from the learned network was subsequently analyzed in the Cytoscape environment. For the workbench lab, whole blood samples were collected from
the MS Research Center and Al-Zahra Hospital in Isfahan, Iran, between June 2019 and October 2019. RNA extraction was conducted in the laboratory at Isfahan University.
Real-time PCR (RT-PCR) was employed to validate the expression changes of the candidate mirRNAs (hsa-miR-520d-3p, hsa-miR-449a).
The results were analyzed using REST 2009 software.

The Notch1 signaling pathway was targeted by hsa-miR-520d-3p and hsa-miR-449a in MS patients, which led to downregulation of critical genes,
such as LIM and SH3 protein 1 (LASP1), Tubulin Alpha1c (TUBA1C), and S100 calcium binding protein A6 (S100A6).
Furthermore, the results from RT-PCR among 50 whole blood samples,
comprising 30 cases of MS and 20 control cases, indicated that the expression levels of miRNA in patients with MS exhibited a statistically significant difference compared to those
in healthy individuals, with values of 0.324 for hsa-miR-520d-3p and 0.075 for hsa-miR-449a.
These values correspond to a downregulation of 3.1-fold and 13.3-fold, respectively.

The findings indicate that MS patients have lower expression levels of hsa-miR-520d-3p and hsa-miR-449a.